Ok, so I have been wearing the MW75 for a little close to 6 hours now. I am very tired of wearing them. They are not an all-day pair of headphones for me, mainly because of the earpad size!
I will focus on just comparing the MW75 to the MG20. These two headphones share a lot of similarities.
Quality, size, and weight
The MW75 feels like it is of much nicer quality. The leather, the aluminum ear cups on the MW75 vs the plastic earcups on the MG20, the buttons, etc. The MG20 is excellent, but compared to the MW75, it feels more plasticy and has lesser quality. Even the headbands on both are lamp skin, but the MW75 feels like it was made with better quality. That said, the hinges and the size adjustment are almost identical. I found the clamping force to be about the same as well. It's like they were both made with the same frame except different components.
The MG20 ear cups can fold in, or out. The MW75 ear cups can only fold in (Why M&D?)
I like the scroll wheels on the MG20 more than the buttons on the MW75. The scroll wheels are easier to navigate when you are wearing the headphones. I found myself constantly feeling all the buttons on the MW75 to figure out where I was before pressing anything.
Unsurprisingly, the MG20 weighs less because of all the plastic. But It's a very minor difference. Personally, if I had to hold one and then the other, I wouldn't be able to tell the difference. But with holding them both at the same time you could tell the MG20 is slightly lighter.
Ear pads
Did they make the MW75 ear pads for kids? I don't understand why they are so small! What is crazy is that the ear cups on both headphones are identical in size! The outside of the ear pad sizes are also almost identical. It's the middle ear space that is very small. The ear pads that come with the MW75 are thicker, which makes the center a lot smaller.
To add insult to injury, the MG20 has 50mm drivers, while the MW75 has 40mm drivers. They use the exact same size housing, so you would think the ear pads would be the same? Nope! They decided to make the MW75 ear pads smaller for whatever reason!
I looked at their site, and the pictures they posted for replacement ear pads for both the MG20 and the MW75 look almost identical. If anything, the MW75 ear pad pictures look bigger than the MG20 ear pad pictures, but in reality, they are the opposite. I emailed their support to see if they updated their design by any chance, but I doubt they did! I hope to hear back from them and will go from there. I actually might return these headphones for this reason.
App
The app is meh at best. But I already knew that from using the MG20. I don't care too much about apps in general since most of the stuff is set it and forget it for me. You can change the EQ presets, ANC volume, and audio prompts. One thing I found weird is if you turn the audio prompts off, I expected to hear single/double/etc confirmation dings, but nope, you just don't hear any prompts at all. If audio prompts are off, there is no way to tell which ANC setting you are on. You would have to listen and guess.
Other than the few toggles, there isn't much going on here. I was already on the latest firmware.
Sound quality
I found the MW75 to be bass-heavy right out of the box. I had to change the preset in the app to "BASS CUT" which matched the default no preset sound on the MG20. Both headphones sound great, and I am sure many people would be pleased with one or the other. With A/B testing, I like the sound eq (with BASS CUT) of the MW75 more than the MG20. The MW75 sounded more detailed than the slightly more V shape of the MG20. Since the MG20 is mainly a gaming headset, the default preset is tuned with somewhat more treble and less mid-range.
I mainly listen to rock music, and with the MW75, the instruments' separation sounded much more alive and fun. With that said, I bet you could make both headphones sound exactly the same with proper EQ. The MG20 might sound even better due to the 50mm beryllium driver, compared to the 40mm beryllium driver on the MW75.
Wired mode
This is mentioned on the site, but the MW75 has two different passive-wired modes. You can use the 3.5mm to USB-C cable for analog passive mode, and it will work with the headphones off and no ANC. Or, use the USB-C to USB-C digital passive mode, but the headphones will need to be on, and you can use ANC. I haven't compared the sound quality of the two modes.
You get the 1m long cables with the MW75. The MG20 includes the 2m cables. In the picture below I am using the 2m 3.5mm to USB-C cable I got with the MG20.